This application claims the priority of German Application No. 100 26 026.8, filed May 25, 2000, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a head protection system for occupants of motor vehicles having an inflatable air bag which, as required, is filled by a gas generator and which, in the inflated condition, extends laterally between the vehicle occupant""s shoulder and head.
A head protection system of this type is known from European Patent Document EP 0 592 815 B1. An air bag is arranged on the upper section of a seat belt designed as a diagonal belt and is fastened by one end to the B-column of the vehicle body. The gas generator for filling the air bag is also situated in this area. The air bag is cut such that it forms a V-shape when inflating. The V-legs, which extend toward one another, point to the vehicle occupant""s neck region.
In order to achieve its protective effect, the known head protection system must be inflated very rapidly; that is, the air bag must be filled at a high pressure. Only in this manner will it be ensured that, in the event of a lateral impact, the vehicle occupant""s head will already be supported at the beginning of its displacement by the then already inflated air bag. Such a rapid filling of the air bag is also paraphrased as the xe2x80x9caggressivenessxe2x80x9d of the system.
It is an object of the invention to further develop a head protection system of the above-mentioned type such that it exhibits a lower aggressiveness and, furthermore, can be used universally, that is, also in open vehicles, such as convertibles.
According to the invention, this object is achieved by providing a head protection system for occupants of motor vehicles having an inflatable air bag which, as required, is filled by a gas generator and which, in the inflated condition, extends laterally between the vehicle occupant""s shoulder and head via seams, which define the individual wall sections of the air bag with respect to one another, the air bag is designed as a multi-chamber air bag with mutually connected partial chambers. The chambers provide the air bag in the inflated condition with an approximate L-shape, with a lower chamber which extends approximately horizontally along the vehicle occupant""s shoulder, and at least one additional chamber which is upright thereto and extends upward along the neck and head area. The gas for inflating the air bag is fed into the upright chamber. The chambers support one another in the inflated condition. Further developments of the invention are described herein.
According to the invention, the air bag is therefore divided into several chambers which are connected with one another, so that the gas generated by the gas generator can flow from one chamber into another. As a result of their design, the chambers provide the air bag with an L-shape with a lower chamber which, similarly to the horizontally extending L-leg, extends along the vehicle occupant""s shoulder. This is adjoined, corresponding to the perpendicular L-leg, by a second upright chamber which extends upward along the vehicle occupant""s neck and head region.
This arrangement allows the upright chamber to be filled first. As a result, the occupant""s head already finds a certain support on this air bag section at the beginning of its displacement. This air bag section also protects the occupant""s head from vehicle body parts that penetrate toward it. The gas flows from the upper chamber into the lower chamber, which also fills up. Thus, in the event of a further displacement of the head, the upper chamber can support itself against the finally filled lower chamber, so that, on the whole, the vehicle occupant""s head is held in a secure manner. Because of the resulting longer filling time, the system exhibits a less aggressive nature.
The invention is particularly suitable for open vehicles, such as convertibles. In the case of these vehicle types, no vehicle body sections exist in the form of B- or C-columns. The fixing of the head protection system according to the invention takes place in such cases in the area of the upper edge of the backrest of the vehicle seat. The gas generator itself can preferably be accommodated in the backrest or the headrest. To the extent that these seats are equipped with a so-called integrated belt systemxe2x80x94all belt anchoring points are provided in or on the seatxe2x80x94, it is expedient to anchor the air bag on the belt strap. This can take place in a simple manner by a loop on the exterior side of the air bag through which the belt strap is guided.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.